1) Field of the Invention
The present invention relates to vehicle mirror assemblies, and more particularly, to a vibration resistant connector for attaching a mirror support arm to a vehicle mount attached to the vehicle body.
2) Description of Related Art
A problem with large exterior side view vehicle mirror assemblies carried by commercial tractor-trailers and other large vehicles is that the vehicles produce constant vibration, which caused the connection of the mirror assembly to the vehicle to loosen over time. Typically, the vehicle mirror assembly includes large tubular frame member which carries the mirror assembly. The tube frame is then affixed to a vehicle mounted attachment by way of a tube connector. The connection between the tube connector and the tubular frame is where vibrations cause the components to loosen.
Typically, the connection between the tube frame and the tube connector is accomplished by one of several ways. One way of connecting these components is by a press fit which essentially squashes the tube frame to the tube connector. The press fit has resulted in numerous problems, however, such as the cracking and breaking of parts under pressure and generally loose connections. When the press fit does not provide a tight connection, screws are used to attempt to resolve the problem, but it has been found that over time the screws can loosen up through vibration and cause the parts to wear on each other and eventually fail.
Another way of attaching the tube frame to the tube connector involves the use of glues. Gluing the parts together presents many manufacturing problems as the components must sit a certain amount of time to cure. Additionally, gluing is more expensive and has not produced a dependable vibration resistant connection.
Yet another way to attach the tube frame to the tube connector is to cut notches into the tube connector and then press the tube frame into the notches. This has had some success when using carbon steel tubing with minimal rebound memory. Stainless steel tubing, however, springs back to far to provide a reliable tight connection. Pressing the steel tubing far enough to compensate for this spring back typically breaks the tube-connector, which is usually made of aluminum.
Alternatively, some skilled in the art have attempted to get rid of the tube connector entirely by flattening the end of the tube frame and bolting it directly to the vehicle mounted attachment. However, this does not provide a good joint between the components and loosens up over time due to vibration.
U.S. Pat. No. 4,565,345 discloses a mirror assembly that includes an expandable ball and socket arrangement for selectively retaining a mirror in a desired rotational position relative to the vehicle. The expandable ball comprises a plurality of partially spherical segments which expand outward from an axial bore when a draw bolt is received through the ball. The spherical segments then bias against the socket to hold the mirror in position. This invention is not directed to providing a sturdy connection for large tubular frame members carrying mirror assemblies of the type found on commercial tractor-trailers. Rather this connector was designed simply to hold a small mirror of the type found on passenger vehicles in a fixed position, and is not intended to serve as a structural support for carrying and attaching large mirror assemblies to a vehicle.
U.S. Pat. No. 5,419,522 discloses an adjustable mount having a pair of ball and socket units in which a screw engages a wedge, which in turn forces a pair of plungers to engage ball elements that hold the adjustable mount in a desired position. As the screw is tightened, the wedge is drawn upward which forces the plungers laterally to engage the ball elements. This connector assembly is intended to allow the mirror to be easily repositioned by loosening and tightening of the screw and there is no suggestion that this connector could be useful in securing large mirror assemblies to vehicles.
Accordingly, it is an object of the present invention to provide a vibration resistant connector assembly for affixing a mirror support arm carrying a mirror assembly to a vehicle mount so that vibration caused by driving of the vehicle do not cause the connection to become loose.